1. Field of the Invention:
This invention relates to a binding-up band (a metal band) for use in fastening articles having remarkable shrink properties, such as cotton or the like, and more particularly to a binding-up band with locking structures in which the ends of the band are interconnected to each other by mutually fitting in projections formed on the ends thereof by providing cuts in the ends of the band and pressing out the cut-provided portions.
2. Statement of the Prior Art:
Broadly speaking, there are two ways of fastening articles utilizing a metal binding-up band manufactured of band steel: one is a way of fastening with seals (1); and the other a way of fastening without seals, that is, a seal-less fastening (2). A sealer is required when fastening is performed by means of the way of fastening with seals (1), while, in the way of seal-less fastening (2), fastening of the band is achieved by engaging means provided on the band itself, and no sealer is required in fastening the band. Thus, it is an advantage of the latter way that it enables a simple and quick bundling operation. Recently, this seal-less fastening way has been widely adopted.
It is common practice in the seal-less fastening method to fasten a band by mutually engaging locking portions provided on the ends thereof, and a locking structure disclosed in an Official Gazette of Japanese Patent Publication No. 39-13748 has been widely employed.
This widely employed locking structure adopts a method in which the ends of a band are overlapped and are detachably interconnected by means of irregular fitting of the ends thereof. FIGS. 13 and 14 show a concrete example of this method, in which pairs of symmetrical bent cuts are provided in the ends 11, 21 of the distal portions 1, 2 of a band, and the cut-provided portions are pressed out to form raised locking portions 101, 201 of the same length and each having a wide portion Wa and a narrow portion Wb for irregular fitting. When tensile force is applied to the band in a longitudinal direction (shown by the arrow A) in such a fitted condition, the wide portion Wa on the male end of the band and the narrow portion Wb on the female end thereof are caused to vertically overlap each other, whereby the ends of the band are interlocked.
This locking structure eases fastening and provides sufficient resistance to stretching. Therefore, the structure is well suited to bundling up articles having remarkable shrink properties such as cotton or the like.
However, this locking structure according to the prior art has a risk in that the locking portions at the extreme ends of the engaging area on the female end are subject to breakage since tensile force is applied thereto to a maximum extent when a tensile force is applied to the band in a longitudinal direction. When the band is broken, the locking state of the band is then released, the goods bundled thereby being caused to fly apart. It is very dangerous if this happens during a loading operation.
To cope with this, Sumitomo Metal Industries, Ltd. filed with the Japanese Patent Office on July 24, 1987 an application of the invention entitled, "Locking Structure for Binding-up Band" (Japanese patent application Nos. 62-185786 and 62-185787) in which loosening or breakage of the fastened portion of the band is protected.